Spray Pyrolysis Synthesis of Mesoporous Positive Electrode Materials for High Energy Lithium-Ion Batteries

Abstract

A lithium metal oxide positive electrode material useful in making lithium-ion batteries that is produced using spray pyrolysis. The material comprises a plurality of metal oxide secondary particles that comprise metal oxide primary particles, wherein the primary particles have a size that is in the range of about 1 nm to about 10 μm, and the secondary particles have a size that is in the range of about 10 nm to about 100 μm and are uniformly mesoporous.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a non-provisional application claiming the benefit of U.S. Provisional Application No. 61 / 481,601, filed May 2, 2011, which is incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]This invention was made with Government Support under a grant from the National Science Foundation (grant CBET-0928964). The government has certain rights to this invention.FIELD OF THE INVENTION[0003]The invention is generally related to active materials for battery applications. More specifically, the invention relates to fine structured positive active materials and methods for preparing them for use in lithium-ion batteries.BACKGROUND OF INVENTION[0004]Lithium-ion secondary batteries are considered an attractive power source for portable devices, electric, hybrid electric vehicles, and large renewable power facilities. A Li-ion cell is comprised of an anode and a cath...

AI Technical Summary

Problems solved by technology

Cobalt is toxic and less abundant, thus making it costly compared to Fe, Mn, and Ni.

Advantageously, spinel LiMn2O4 has a flat voltage plateau at 3 V and 4 V, however, severe capacity fading at deep discharge makes it impractical for high-energy battery applications.

LiFePO4 is considered the safest these cathode materials but pure LiFePO4 suffers from a low conductivity at room temperature, compared to LiCoO2 and LiMn2O4.

Furthermore, none of the above materials have shown a capacity higher than 200 mAhg−1 and good capacity retention.

A surface treatment involving acid etching and surface coating with phosphate is known to enhance the rate and cycle capabilities and improve the columbic efficiency of these materials but adds complexity to the synthesis processes.

The process for synthesizing the aforementioned lithium-nickel-manganese oxide includes co-precipitation of transition metal carbonates or hydroxides, post-lithiation, and calcination at high-temperature.7,8 This process resulted in a powder that was polycrystalline and may have a core-shell structure, wherein the core region has a different electron diffraction pattern and preferred-growth direction than that of the shell region.8 While the reported performance of this powder is considered to be excellent, the synthesis process is multistep, slow, energy intensive, costly, prone to variability, and produces considerable waste.

Furthermore, the particle size and morphology are constrained by the co-precipitation method and are believed to be far from ideal, particularly when the method is applied at commercial scale.

Irregular particles, tens of microns in size and often with a cracked interior, may be produced and particle-to-particle and batch-to-batch consistency is a challenge.

Images